The present invention relates generally to automotive frames, and more particularly to automotive frames having rails that absorb kinetic energy in front end crashes.
Automotive manufacturers continuously develop devices intended to improve vehicle safety in front end crashes. Moreover, automotive manufacturers are particularly concerned with vehicle safety in front offset crashes on account of the tendency to cause extensive intrusion into the passenger compartment, such as the toe pan area. Intrusion into the passenger compartment increases the risk of serious injury to the occupants of the vehicle. Such a result is clearly undesirable.
It is well known that deformation of the automotive structure can absorb some kinetic energy from the crash. Accordingly, kinetic energy from the crash may be used to bend the automotive structure instead of causing intrusion into the passenger compartment. As a result, the associated risk of injury can be decreased.
Existing rails have structures that do not permit substantial bending. For example, the rails may bend only one time in a front end crash. Consequently, relatively little kinetic energy is absorbed by the rails.
Furthermore, existing rails absorb even less kinetic energy in front offset crashes. In this regard, only the one rail on the impacted side of the vehicle may be deformed. The opposing rail on the non-impacted side of the vehicle is sufficiently rigid that the bumper beam and cross members may detach from the opposing rail before it bends.
Therefore, it would be desirable to increase the amount of kinetic energy absorbed by rails during front end crashes so as to reduce intrusion into the passenger compartment and the associated risk of injury.
The present invention provides a rail for an automotive frame that absorbs kinetic energy in front end crashes. The rail is a metal bar having a front portion and a plurality of indentations (such as notches or openings) integrally formed therein along the longitudinal axis. The indentations form weakened sections of the metal bar that allow the metal bar to bend and thus absorb more kinetic energy of a front end crash.
One advantage of the present invention is that the rail reduces intrusion into the passenger compartment, especially the toe pan area, and the risk of injury to occupants of the vehicle.
Another advantage of the present invention is that various kinds of rails having different cross-sections may be employed to absorb the kinetic energy of a crash.
Other advantages of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.
FIG. 1 is a perspective view of a front portion of a vehicle having an automotive frame with kinetic energy absorbing rails integrated therein, in accordance with a preferred embodiment of the present invention;
FIG. 2 is a top view of a front portion of a rail for an automotive frame, in accordance with a preferred embodiment of the present invention;
FIG. 3A is a side view of a double cell extruded rail having holes formed therein, in accordance with a preferred embodiment of the present invention;
FIG. 3B is a cross-sectional view of the double cell extruded rail as shown in FIG. 3A, the view taken along line 3Bxe2x80x943B in FIG. 3A;
FIG. 3C is a cross-sectional view of the double cell extruded rail as shown in FIG. 3A, the view taken along line 3Cxe2x80x943C in FIG. 3A
FIG. 4A is a top view of a front portion of an automotive frame having two rails with indentations formed therein, in accordance with a preferred embodiment of the present invention;
FIG. 4B is a top view of the automotive frame shown in FIG. 4A after a 40% offset crash; and
FIG. 5 is a graph illustrating typical force-deformation responses of both a conventional rail lacking indentations and a rail having indentations formed therein, in accordance with a preferred embodiment of the present invention.